ConspectusDiscoveries of novel functional materials have played very important roles to the development of science and technologies and thus to benefit our daily life. Among the diverse materials, metal–organic framework (MOF) materials are rapidly emerging as a unique type of porous and organic/inorganic hybrid materials which can be simply self-assembled from their corresponding inorganic metal ions/clusters with organic linkers, and can be straightforwardly characterized by various analytical methods. In terms of porosity, they are superior to other well-known porous materials such as zeolites and carbon materials; exhibiting extremely high porosity with surface area up to 7000 m2/g, tunable pore sizes, and metrics through the interplay of both organic and inorganic components with the pore sizes ranging from 3 to 100 A, and lowest framework density down to 0.13 g/cm3. Such unique features have enabled metal–organic frameworks to exhibit great potentials for a broad range of applications in gas storage...

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Metal–Organic Frameworks as Platforms for Functional Materials

Metal-organic frameworks (MOFs), also known as coordination polymers, represent an interesting type of solid crystalline materials that can be straightforwardly self-assembled through the coordination of metal ions/clusters with organic linkers. Owing to the modular nature and mild conditions of MOF synthesis, the porosities of MOF materials can be systematically tuned by judicious selection of molecular building blocks, and a variety of functional sites/groups can be introduced into metal ions/clusters, organic linkers, or pore spaces through pre-designing or post-synthetic approaches. These unique advantages enable MOFs to be used as a highly versatile and tunable platform for exploring multifunctional MOF materials. Here, the bright potential of MOF materials as emerging multifunctional materials is highlighted in some of the most important applications for gas storage and separation, optical, electric and magnetic materials, chemical sensing, catalysis, and biomedicine.

Emerging Multifunctional Metal-Organic Framework Materials.

The trade-off between physical adsorption capacity and selectivity of porous materials is a major barrier for efficient gas separation and purification through physisorption. We report control over pore chemistry and size in metal coordination networks with hexafluorosilicate and organic linkers for the purpose of preferential binding and orderly assembly of acetylene molecules through cooperative host-guest and/or guest-guest interactions. The specific binding sites for acetylene are validated by modeling and neutron powder diffraction studies. The energies associated with these binding interactions afford high adsorption capacity (2.1 millimoles per gram at 0.025 bar) and selectivity (39.7 to 44.8) for acetylene at ambient conditions. Their efficiency for the separation of acetylene/ethylene mixtures is demonstrated by experimental breakthrough curves (0.73 millimoles per gram from a 1/99 mixture).

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Pore chemistry and size control in hybrid porous materials for acetylene capture from ethylene

The separation of related molecules with similar physical/chemical properties is of prime industrial importance and practically entails a substantial energy penalty, typically necessitating the operation of energy-demanding low temperature fractional distillation techniques Certainly research efforts, in academia and industry alike, are ongoing with the main aim to develop advanced functional porous materials to be adopted as adsorbents for the effective and energy-efficient separation of various important commodities Of special interest is the subclass of metal–organic frameworks (MOFs) with pore aperture sizes below 5–7 A, namely ultra-microporous MOFs, which in contrast to conventional zeolites and activated carbons show great prospects for addressing key challenges in separations pertaining to energy and environmental sustainability, specifically materials for carbon capture and separation of olefin/paraffin, acetylene/ethylene, linear/branched alkanes, xenon/krypton, etc In this tutorial review we discuss the latest developments in ultra-microporous MOF adsorbents and their use as separating agents via thermodynamics and/or kinetics and molecular sieving Appreciably, we provide insights into the distinct microscopic mechanisms governing the resultant separation performances, and suggest a plausible correlation between the inherent structural features/topology of MOFs and the associated gas/vapour separation performance

Gas/vapour separation using ultra-microporous metal-organic frameworks: insights into the structure/separation relationship.

Separation is an important industrial step with critical roles in the chemical, petrochemical, pharmaceutical, and nuclear industries, as well as in many other fields. Although much progress has been made, the development of better separation technologies, especially through the discovery of high-performance separation materials, continues to attract increasing interest due to concerns over factors such as efficiency, health and environmental impacts, and the cost of existing methods. Metal-organic frameworks (MOFs), a rapidly expanding family of crystalline porous materials, have shown great promise to address various separation challenges due to their well-defined pore size and unprecedented tunability in both composition and pore geometry. In the past decade, extensive research is performed on applications of MOF materials, including separation and capture of many gases and vapors, and liquid-phase separation involving both liquid mixtures and solutions. MOFs also bring new opportunities in enantioselective separation and are amenable to morphological control such as fabrication of membranes for enhanced separation outcomes. Here, some of the latest progress in the applications of MOFs for several key separation issues, with emphasis on newly synthesized MOF materials and the impact of their compositional and structural features on separation properties, are reviewed and highlighted.

Metal-Organic Frameworks for Separation.

The removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene is a technologically very important, but highly challenging task Current removal approaches include the partial hydrogenation over a noble metal catalyst and the solvent extraction of cracked olefins, both of which are cost and energy consumptive Here we report a microporous metal-organic framework in which the suitable pore/cage spaces preferentially take up much more acetylene than ethylene while the functional amine groups on the pore/cage surfaces further enforce their interactions with acetylene molecules, leading to its superior performance for this separation The single X-ray diffraction studies, temperature dependent gas sorption isotherms, simulated and experimental column breakthrough curves and molecular simulation studies collaboratively support the claim, underlying the potential of this material for the industrial usage of the removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene at room temperature through the cost- and energy-efficient adsorption separation process

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Microporous metal–organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

Utilizing transient breakthroughs for evaluating the potential of Kureha carbon for CO2 capture

Preparation of mesoporous mordenite for the hydroisomerization of n-hexane

RuO2/TiO2 catalysts with different TiO2 crystal sizes were prepared via a dry impregnation method, and these prepared catalysts were applied in the oxidation of HCl. The results show that decreasing the support-crystal size is an effective method to enhance the dispersion of RuO2 on TiO2, which is helpful to increase the catalytic activity significantly.

Effects of the Support-Crystal Size on the Catalytic Performance of RuO2/TiO2 in the Deacon Process

The invention relates to a CaF2 material for absorbing trace water in HF gas and a preparation method thereof. The CaF2 material is synthesized by taking Na3C6H5O7.2H2O as a complexing agent, Ca(CH3COO)2 as a calcium source and NaBF4 as a fluorine source through a hydrothermal method; the mol ratio of the Ca(CH3COO)2 to the Na3C6H5O7.2H2O to the NaBF4 is 1 to 5 to 2. The CaF2 material prepared bythe method has good thermal stability, has excellent water absorption performance under ultralow water vapor pressure and can be used for effectively absorbing the trace water in the HF gas to prepareHF high-purity electronic gas.

Wang Xue

Papers

Microporous metal–organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

Utilizing transient breakthroughs for evaluating the potential of Kureha carbon for CO2 capture

Preparation of mesoporous mordenite for the hydroisomerization of n-hexane

Effects of the Support-Crystal Size on the Catalytic Performance of RuO2/TiO2 in the Deacon Process

CaF2 material for absorbing trace water in HF gas and preparation method thereof